CFRN vs CEN

[FiremedicMike, BSN, RN, EMT-P]

Just wondering..

I have prior flight experience as a medic, passed my FP-C on the first try.  Im currently an ED nurse and also passed my CEN on the first try.

I'm going to start stacking my resume to get back to the helicopter and plan on taking my CFRN prior to applying.  I'm just wondering how difficult the CFRN is compared to the CEN and FP-C?

Especially interested to hear from anyone who had one of those prior certs before taking the CFRN.

Thanks!